Boiler thermocouple question

parking_question_chap

Hi

Is it possible to determine if a thermocouple is nearing the end of its life?

We had our very old and basic boiler serviced 2 weeks back. Nothing was changed and we paid the £50 (gas safe registered chap). Boiler has been used a few times since then with no issues.

Today the pilot light went out, and not wanting to test anything myself I called the same chap. I have been told he will come out on Tuesday and replace the thermocouple. I am just surprised they know the problem before even looking at it.

Chap seems genuine, but I just wanted to double check. More for the fact we will probably getting boiler replaced soon and are on the lookout for a trusworthy trader.

Gloomendoom

Sounds like a reasonable assumption to me.

If he fixes it, I wouldn't be in a hurry to replace the boiler. Basic has less to go wrong.

EssexExile

I assume he'll replace the thermocouple because it's quick & cheap. If that doesn't sort it he'll look further.

And yes, if he's good hang on to him!

southcoastrgi

Have you re-lit the boiler ?

missprice

You/gas safe engineer can hazard a reasonable guess re thermocouple.
Its also cheap to replace.
Last one I got replaced was a whole £7. And took less than 20 mins to fit.

As gloomendoom says basic means less to go wrong.

parking_question_chap

southcoastrgi wrote: »

Have you re-lit the boiler ?

Not even going to try, I am to DIY what Wayne Rooney is to Quantum Mechanics.

Plus there is a chance its a positive pressure boiler (model has several variants and I dont know which one ours is) so I need to make sure its sealed up correctly.

southcoastrgi

What boiler is it ?
You don't need to access anything to try to relight the pilot there should be instructions somewhere on the boiler,
You are going to be without hot water & heating for 5 days & maybe just because it's blown out

parking_question_chap

Thorn Olympic. We dont know which model number and have no instructions. Anyhow, the only button on the front is 1-5 for the level of heating.

We have a switch for hot water upstairs so that isnt an issue. Plus its not really that cold so no hurry.

Mr.Generous

Thermocoupe is most likely reason, however when he serviced the boiler he should have cleaned it - a flame plays on the thermocoupe and it gets a carbon build up. If the carbon builds up too thick the thermocouple doesn't get hot enough to keep the gas flowing so does its job and switches off the gas feed. Im guessing he did clean it, but they have to be lined up accurately and tightened up in the correct place, the thread and two lock nuts allow adjustment. It could be as simple as re aligning the coupling. If it hasn't been changed for 2 years or more I'd definitely get a new one anyway, they don't make 'em like they used to and it will fail sooner or later! I really would relight it thought, you absolutely can't do any harm, the thermocouple is basically a flame failure device that will prevent gas being continuously released if the pilot goes out. Remove the cover on the boiler and the instructions will be printed inside.

parking_question_chap

Yes, I can confirm it was cleaned. I was in the kitchen for a few minutes and happened to observe some clearning of the mechanism and hoovering out/wiping the cover.